Yeast-wort and method of producing the same.



OSWIN W. WILLCOX, OF DOVER, NEW JERSEY.

YEAST-W031 ANT) METHOD OF PRODUCING THE SAME.

No Drawing.

Specification of Letters Patent.

Patented Nov. 19, 1912.

Application filed April 29, 191a. Seria'i No. 693,944.

. To all whom it may concern:

Be it known that I, OSWIN IV. lVlLLoox, a citizen of the UnitedStates,'- residing at Dover, in the county of Morris and State of NewJersey, have invented certain new and useful Improvements in Yeast-Wortand Method of Producing the Same; and I do hereby declare the followingto be a full, clear,,and exact description of the invention. such aswill enable others skilled in'the art to which it appertains to make anduse the same.

The present invention relates, generally, to a novel composition ofingredients pro riding a wort for the culture, production andmanufacture of yeast, and t-heinvention also relates'to the novelprocess or method of producing said wort.

The present invention has for its principal object to provide a processwhereby waste' sulfite liquor, which in its original condition isunsuitable. for yeast manufacture, is subjected to appropriate chemicaltreatment and addition of chemicals, whereby a novel and suitable mediumor wort adapted to support the vigorous maximum growth and developmentof culturev yeast is obtained.

As is well known, in the sulfite process of paper manufacture, wood, inthe form of chips, is placed in an apparatus called a digcster, whereinit is SUbJGCtQd to a cooking process in the presence of 'a solution ofcalcium sulfite produced by passing gaseous sulfur dioxid into a mixtureof lime and water. In the course of this cooking rooess the ligninsubstances of the W005 dissolved, leaving the cellulose of the wood in aform suitable for paper making. After {the mass of wood has been thuscooked, it removed from the digester into a tank,

from whence the sulfite solution, containin the matters it has dissolvedfrom the wood:

is allowed to drain oil from the wood pulp.

I This waste sulfite liquor is generally thrown away, or allowed todrain off into a stream in the neighborhood of the paper or pulp mill.This waste sulfite liquor contains a certain amount of fermentablesugars and potassium salts. which .renders it, when subjectcd tosuitable chemical treatment and the addition of suitable chemicals, afavorable base for the production of a wort for yeast manufacture. Atypical example of such Waste sulfite liquor contains about are poisons,so much so that when present in such amounts as. normally contained inthe waste sulfite liquor, neither yeast, molds nor bacteria can growtherein. In its original or normal condition therefore the waste sulfiteliquor, while containing some elements favorable to the composition ofayeast wort, is wholly unsuitable for yeast culture or production, and reuires chemical treatment and addition of c emicals which will. destroyits toxic properties toward yeast. Not only must the toxicity beremoved, but there must also be added to the liquor further elementswhich the yeast must have if it isto grow and multiply to its fullestcapacity. The absent elements which are lacking in the waste sulfiteliquor are nitrogen and phosphoric acid in suitable form and amount,only slight traces of which exist in the normal constituency of thewaste sulfite liquor.

The first step, then, in making the waste sulfite liquor suitable for awort to be used in yeast manufacture, is to bring down or reduce itsacidity to and at the same time secure the introduction of nitrogen insuitable form and amount. By bringing down or reducing the acidity ofthe waste sulfite liquor within proper limits, I mean, that the aciditvof the waste sulfite liquor need not be entirely neutralized, but thataslight amount of acidity may be left, for example the acidity may beneutralized to within 0.2%, expressed as ammonium bisulfite. The reasonfor leaving this slight amount of acidity is that culture yeastisindifferent to the small amount of ammonium bisulfite involved, while,on the other hand, the presence of this small amount of ammoniumbisulfite prevents th'e'growth and development of wild yeasts andundesired'bacteria, the result being that the yeastcrop propagated in1.89% of fermentable sugars, and a mineral. ash conslstmg largely ofcalcium salts but however, contains fairly large within proper limits,

the wort so constituted is practically pure, and is not so easilysubject :tosp01lage and deterioration as the yeast grown or defiteliquor. In proceeding to carry out this a nitrogen, I complete thenecessary amount sulfite liquor to be treated.

first step in the preparation of the waste sulfite liquor as a wort, inother words, to

neutralize the liquor to the extent above indicated, I add ammoniain-the form of aqua ammonia or liquid ammonia. The e ect or chemicalaction of this addition is to partially neutralize the acidity of thewaste sulfite liquor, and to add thereto the requisite quantity ofnitrogen. The amount of ammonia necessary will vary according to thecircumstances, and is to be determined by the amount of fermentablesugars present and the free acidity in the waste My aim is to alwaysintroduce nitrogen, in the form of ammonia, to the amount of about 5% ofthe dry weight of the yeast crop expected. Thus, for example, to obtaina yield of compressed yeast equivalent to 20% weight of the fermentablesugars present in the solution, nitrogen, in the form of ammonia, equalto about 0.25% of the weight of the fermentable sugars. When, as theresult of experiment, I find that the addition of larger quantities ofammonia results in an increased yield of yeast, I increase the minimumamount of ammonia to be added; and, conversely; when I find that asmaller quantity of nitrogen will give the same 'eld of yeast, I loweror reduce the amount of ammonia to be added, always bearing in mind thatthe yeast is to be supplied with nitrogen, in the form of ammonia, in noless quantity than it can assimilate under conditions favorable forobtaining the yeast crop expected. I regard, however, the 0.25% ratio'ofnitrogen to the fermentable sugars, as above indicated, to be the practical minimum of nitrogen to be added in order to produce a wort mostfavorable to yeast development, and the maximum production of new cells.

The acidity of the waste sulfite liquor may be first reduced by addingaqua ammonia or liquid ammonia in sufiicient quantity to reduce theacidity to the required point, that is to neutralize the free acidity towithin 0,29%. 7 If such added ammonia is not suflicient to supply thenecessary amount of of the latter by the addition of some neutral saltof ammonia, such as ammonium sulfate or ammonium chlorid, which whileadding to the amount of nitrogen will not disturb the balance of aciditydesired to be maintained in the solution. If, however, to neutralize thesulfite liquor to the desired balance of acidity requires more ammoniathan is needed for the yeast crop expected, I'first partially neutralizethe acidity with lime, or carbonate of lime, and then finish theneutralization to within the required limits yeast equivalent to 20% ofthe "I would employ an amount of by ammonia sufiicient to also supplythe requisite amount of nitrogen.

The next step in preparing fite liquor as a wort for yeast is to add tothe neutralized and nitrogen-supplied solution, obtained as above thewaste sulthe manufacture of.

described, an amount of phosphoric acid suflicient to meet therequirements of the yeast crop expected. Yeast contains about 3% ofphosphoric acid on the average, so in order to secure an amount ofcompressed ofthe weight of the fermentable sugars contained in the wort,(maintaining by Way of example the illustrative quantity of the yeastcrop above mentioned) I add phosphoric acid to the amount of about 0,16%of the weight of the fermentable sugar contained in the solution. As inthe case of the nitrogen, this proportional amount of phosphoric acidmay be raised or lowered as experience shows is advisable in view of theamount and quality of the yeast crop desired. The phosphoric acid may beadded in the form of free phosphoric acid, or in the form of one of itssalts, such as calcium salts ofphosphoric acid, sodium salts ofphosphoric acid, ammonium salts of phosphoric acid, or in general thecombination of phosphoric acid with any soluble, non-poisonous alkalineor alkaline earth base. The increased acidity of the solution or wort,due to the addition of the phosphoric acid or acid salts thereof isallowed for when neutralizing the waste sulfite liquors as abovedescribed, so that the proper balance of acidity is finallymaint-izlined in the completed wort. After having t us requisite toprovide the novel yeast wort, I now proceed to pitch the wort with asuitable quantity of seed yeast, preferably equal to about 20% or 25% ofthe amount of compressed yeast expected. After thus pitching the liquoror wort with the seed yeast, I then subject the li uor or wort toaeration, the amount and uration of the aeration being increased ordiminished according as I desire a larger or smaller crop. After theyeast crop has become ripe, I then proceed to separate it from theliquor in the usual manner, wash it, andform it into the usual tradepackages.

While the steps in the process of preparing the yeast wort, as abovedescribed, and the amountof additional elements added to the wastesulfite liquor to constitute the wort, may be varied, as will be clearlyevident from the above description, it must be clearly understood thatthe of my invention is theuse and treatment of waste sulfite liquors,both in the comp osition of and the preparation of a wort suitable foryeast production, so doing pro 'ding a use fora waste material, as wellas securing a very cheap,

'ven the sulfite liquor a composition.

and manufacture, and in.

cient and desirable wort in which yeast may 7 be cultured and developed,and in which the yeast may produce the maximum number of new cells. 4

I claim v 1. In "the reparation of waste sulfite liquors to pro uce ayeast wort, the addition of ammonia to reduce the acidity of the sulfiteliquor and to supply nitrogen, and the addition of phosphoric acid or asalt thereof.

2. In the preparation of waste sulfite liquors to produce a yeast wort,first reduc ing'the acidity of the waste sulfite liquor with ammonia,increasing the proportion of nitrogen by adding ammonium salts, and thenadding phosphoric acid or a salt thereof.

3. In the preparation of Waste sulfite liquors to'produce a yeast Wort,first par-. tially neutralizing theacidity of the waste sulfite liquorwith lime, finishing the neutralization of acidity of the waste sulfiteliquor to within the required limits with ammonia adapted to also supplya requisite amount of nitrogen, and then adding a requisite amount ofphosphoric acid or salts thereof.

4. A yeast wort comprising the composition of a partially acidneutralized waste sulfite li uor, ammonium salts, and phosphoric aeld ora salt thereof.

5. A yeast wort comprising partially neutralizedwaste sulfite liquorcontaining fermentable sugars and potassium salts, nitrogen in the formof ammonium salt equal to 0.2% of the weight of fermentable sugar, andphosphoric acid equal to 0.16% of the 'Weight offermentable sugar,substantially as described.

In testimony that I claim the invention set forth above I have hereuntoset my hand this 24th day of April, 1912.

OSWIN W. WILLCOX.

Witnesses:

GEORGE D. Rromnns, MAYBELLE McAnoo.

